Advertisements
Advertisements
Question
Write the electronic configuration of K and Ne.
Advertisements
Solution
| Element | Electronic configuration |
| K | 2,8,8,1 |
| Ne | 2,8 |
APPEARS IN
RELATED QUESTIONS
Study the following table in which positions of six elements A, B, C, D, E and F are shown as they are in the modern periodic table:
|
Group→
Period↓ |
1
|
2
|
3-12
|
13
|
14
|
15
|
16
|
17
|
18
|
| 2 | A | B | C | ||||||
| 3 | D | E | F |
On the basis of the above table, answer the following questions:-
(i) Name the element which forms only covalent compounds.
(ii) Name the element which is a metal with valency three.
(iii) Name the element which is a non-metal with valency three.
(iv) Out of D and E, which is bigger in size and why?
(v) Write the common name for the family to which the elements C and F belong.
An element 'X' belong to 3rd period and group 13 of the Modern Periodic Table.
(a) Determine the valence electrons and the valency of 'X'.
(b) Molecular formula of the compound formed when 'X' reacts with an element 'Y' (atomic number = 8).
(c) Write the name and formula of the compound formed when 'X' combines with chlorine
An element 'X' has mass number 35 and number of neutrons 18. Write atomic number and electronic configuration of 'X'. Also write group number, period number and valency of 'X'.
The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons in the outermost shell respectively. State the period in which these elements can be placed in the modern periodic table. Write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine.
Write the number of horizontal rows in the modern periodic table. What are these rows called?
Classify the following elements into metals, non-metals and metalliods
As, C, Hg, Mg, S, Si
An element with the atomic number 19 will most likely combine chemically with the element whose atomic number is ______.
The following table shows the electronic configuration of the elements W, X, Y, Z:
| Element | w | x | y | z |
| Electronic configurations |
2, 8, 1 | 2, 8, 7 | 2, 5 | 1 |
Answer the following questions based on the table above:
1) What type of Bond is formed between :
a) W and X
b) Y and Z
2) What is the formula of the compound formed between :
a) X and Z
b) W and X
An element Z has atomic number 16. Answer the following questions on Z:
1) State the period and group to which Z belongs
2) Is Z a metal or a non-metal?
3) State the formula between Z and hydrogen
4) What kind of a compound is this?
The atomic radii of three elements X, Y and Z of a period of the periodic table are 186 pm; 104 pm and 143 pm respectively. Giving a reason, arrange these elements in the increasing order of atomic numbers in the period.
How do atomic structures (electron arrangements) change in a period with increase in atomic numbers from left to right?
Why do elements in the same group show similar properties but the elements in different groups show different properties?
Which of the following element does not lose an electron easily?
(a) Na
(b) F
(c) Mg
(d) Al
The correct increasing order of the atomic radii of the elements oxygen, fluorine and nitrogen is:
(a) O, F, N
(b) N, F, O
(c) O, N, F
(d) F, O, N
Which one of the following does not increase while moving down the group of the periodic table?
Which of the following set of elements is written correctly in the order of their increasing metallic character?
(a) Mg, Al, Si
(b) C, O, N
(c) Na, Li, K
(d) Be, Mg, Ca
What do you understand by orbits?
State the valency of the elements of periods 3 and write the formula of their oxides.
How does the number of:
valency vary on moving from left to right in the second period of the periodic table?
Name the element which has the electronic configuration 2, 8, 3?
State the number of elements in periods 1, Periods 2, and Period 3 of the periodic table. Name them.
name the elements in period 1.
How do you calculate the possible valency of an element from the electronic configuration of its atoms?
Name the elements in period 1.
Parts (i) to (v) refer to changes in the properties of elements on moving from left to right across a period of the periodic table. For each property, choose the letter corresponding to the correct answer from the choices (a), (b), (c) and (d).
(i) The non metallic character of the elements:
(a) Decreases
(b) Increases
(c) Remains the same
(d) Depends on the period
(ii) The electro negativity
(a) Depends on the number of valence electrons
(b) Remains the same
(c) Decreases
(d) Increases
(iii) The ionization potential
(a) Goes up and down
(b) Decreases
(c) Increases
(d) Remains the same
(iv) The atomic size
(a) Decreases
(b) Increases
(c) Remains the same
(d) Sometimes increases and sometimes decreases
(v) The electron affinity of the elements in groups 1 to 7:
(a) Goes up and down
(b) Decreases and then increases
(c) Increases
(d) decreases
Choose the most appropriate answer from the following list of oxides which fit the description.
An amphoteric oxide: Al2O3 (shows both acidic and basic properties)
Use the letters only written in the Periodic Table given below to answer the questions that follow:
(a) State the number of valence electrons in the atom J.(b) Which element shown forms ions with a single negative charge?
(c) Which Metallic element is more reactive than R?
(d) Which element has its electrons arranged in four shells?
Arrange the following as per instruction given in the bracket.
Cs, Na, Li, K, Rb (decreasing electronegativity)
The elements of one short period of the periodic table are given below in order from left to right:
| Li | Be | B | C | O | F | Ne |
To which period do these elements belong?
With reference to the variation of properties in the Periodic table, which of the following is generally true?
Write the electronic configuration of two elements A and B whose atomic numbers are 20 and 17 respectively. Write the molecular formula of the compound formed when element A reacts with element B. State whether this compound is acidic, basic or neutral. Give a reason to justify your answer.
Supply the missing word from those in bracket:
If an element has one electron in its outermost energy level [shell] then it is likely to be _______.
State the property trends in general of elements on moving down in a group of the periodic table.
Name or state following with reference to the element of the first three periods of the periodic table.
The valency of elements in group 1 [I–A].
Name or state following with reference to the element of the first three periods of the periodic table.
A non-metal in period 2 having electronic configuration 2, 6.
Give a reason for the following:
A transition from metallic to non-metallic elements is seen on moving from left to right in a period of the periodic table.
State the following:
The group which contains highly electropositive metals including sodium.
Complete the table pertaining to the following elements given in Column I.
| Column I Elements | Atomic Number | Electronic Configuration | Underline the element present in that group |
| 1. Hydrogen | 1 | ______ | Be/Na/Ca |
| 2. Carbon | 6 | ______, ______ | N/P/Si |
| 3. Nitrogen | 7 | _______, ______ | C/P/S |
| 4. Oxygen | 8 | _______, ______ | N/S/Cl |
| 5. Sulphur | 16 | _____, ______, _______ | O/N/F |
| 6. Chlorine | 17 | _____, ______, ______ | I/O/S |
